There's no need to thank us, we're a family, and we stick together. We always have, we always will. I met Monty once at RTX, and he was one of the coolest, most down to earth men I've ever met in my life. It's so sad to hear about his passing, my heart is with his families, be it immediate, extended, or Roosterteeth.

Start with Rage Quit: Slender. It's a classic.
If she likes Michael and Gavin, go to Surgeon Simulator next.
When she's ready for a full Let's Play, let's say Minecraft, I recommend Shopping List. It's very long but in my opinion it's one of their best ones. Episode 2: On A Rail is also very good.
The best GTA ones are probably Cops and Crooks in GTA4 and Train Hopping in GTA5. Of course, that's also my opinion.